Ments



(No Model.)

0. E. SGRIBNER. CIRCUIT FOR ANNUNOIATORS 0E TELEPHONE EXGHANGES. No. 266,319. Patented Oct. '24, 1882..

ilNrTEn STATES PATENT O rrrcn.

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO THE WESTERN ELECTRIC COMPANY, OF SAME PLACE.

CIRCUIT FOR ANNUNCIATORS OF TELEPHONE-EXCHANGES.-

SPECIFICATION forming part of Letters Patent No. 266,319, dated October 24, 1882.

Application filed November 3, 1880. (No model.)

To all whom it may concern:

Be it known that I, CHARLES E. SGRIBNER, a citizen of the United States, residingat Chicago, in the county of Cook and State of Illi- 5 nois, have discovered certain new and useful improvements in circuits for annunciators of telephone-exchanges where some or all subscribers are provided with complete metallic circuits, of which the following is a full,- clear, concise, a11d exact description, reference being had to the accompanying drawings, forming a part of this specification.

In the drawings, Figure 1 shows a switchboard which is provided with a switch for each I subscriber. Fig. 2 shows direct connections between two switches.

The switches shown are more particularly described in my application for a patent filed September 18, 1879.

A single switch must be provided on the switch-board, or, in case of duplicate boards, on each board for each subscriber.

The switch or b0lt A is represented in Fig. 1 as connected with a subscriber by a complete metallic circuit, as indicated. The complete circuit is as follows: from the subscriber by line a, through the contact-points of the switch, and'by line a, through a number of an annunciator, and thence by line a to insulated me- 0 tallic plate, and by line a back to the subscriber. Another subscriberis connected with switch B in the usual manner by a single line grounded at both ends. The circuit is from the subscriber byline b, through the contact-points 5 of the switch, and by line b, through the number of annunciator, and by line I) directly to ground. The insulated metallic plate of the switch B is connected directly to ground by wire 11 In Fig. 2 I have shown switches A and B detached from the board, and connected by a double cord with one of my plugs at each end. The point of the plug consists of the portion 0 and the collar 0, which are insulated by hardrubber bushing 0 One insulated wire of the cord is connected with the central part, c, and the other wirewith the collar 0. Hence the two ends of the insulated conductors of the cord terminating in a plug are insulated by the rubber or other insulating substance which separates the central metallic portion of the plug from the metallic collar. A subscriber signals the central office in the usual way by a battery or magneto-generator, and by means of his annunciator informs the attendant, who, by connecting his own telephone, cuts out the annunciator. When allthings are ready the attendant connects the subscribers two switches, as shown in Fig. 2, and the circuit is as follows: from subscribers telephone by line b to bolt B, thence through central portion, 0, and strand of cord connecting said central portions, 0, of the plugs to bolt A, thence by line a to the second subscribers telephone, thence through telephone and by return-wire a to insulated plate of the switch A, thence from collar 0 through the other strand of the cord to collar 0 ofthe plug at switch B, and thence by insulated plate and wire b to ground. Thus the two subscribers are connected, and the returnwire of the one who has a complete metallic circuit is disposed of by ground-connection at the central office.

In case it is necessary to connect two subscribers who have complete metallic circuits, the plugs are inserted in the same way, and the subscribers will be connected by a complete metallic circuit, and two subscribers with single lines may be connected with equal facility, in which case there is a circuit from groundwire b off through the collar and connectingcord to the collar of the other plug and to ground. The connection between the two subscribers is by their lines through their respective switches and plug-points 0 and the strand ofthc cord connecting the said central points, 0.

The foregoing description is found substantially in my application filed herewith, entitled improvement in plugsfor connecting the lines of subscribers at a telephone-exchange central office, and which therefore I disclaim as to -this application.

My invention consists in placing a clearingout annunciator in the line d d, which connects the central points, 0 c, of two plugs connecting 5 any two subscribers, whether provided with complete metallic circuits or otherwise, in such manner thateither of the subscribers may notify the central office when they are through talking.

The annunciator D may be of any of the nected telephone-lines, ofdouble-pointed plugs, well-known forms, and. the wires (1, d, and 0 one plug inserted in the spring jack-switch of may be connected with binding-posts near the each of the lines, respectively, and an annun- I5 point 0, allowing SllfillClBIll] cord between the ciatoranagnet included in the strand of the 5 binding-posts and plugs, respectively, to reach I cord which connects the central points of the to any part of the board. I plugs, whereby the annunciator is included in The connections between the binding-posts the circuit, whether the plugs are used for conmust be so arranged that the circuit of the necting single lines or metallic circuits.

wires connecting with the points 0 c of the two CHARLES E. SORIBNE t. to plugs will be complete through the annunciator; Vitnesses:

I claim- WALLACE L. DE WOLF,

The combination, in the circuit of two 0011- GEORGE P. BARTON. 

